Various methods for reducing artifacts of an image reconstructed based on projection data collected by scan using a radiation tomography imaging apparatus have been proposed. As one of such methods, a method has been proposed in which a plurality of images lined up in the body axis direction of an imaging object, which are planned to be supplied to an operator, are reconstructed and an imaging process such as a filtering process is performed on the reconstructed images in the body axis direction (for example, see the abstracts of PTL1 and PTL2, etc.).
According to this method, in the reconstructed images, it is possible to retain images depicting the structure of the imaging object in which variation in the body axis direction is relatively gradual, and reduce artifacts in which variation in the body axis direction is relatively sharp.